Keep in mind the following limitations when you migrate your Gateways:
- Self-service migration is not supported on Partner Gateways.
- There will be a minimum service disruption based on the time taken to switch Non SD-WAN Destinations (NSDs) from the quiesced Gateway to the new Gateway and to rebalance the Edges connected to the quiesced Gateway.
- If the NSD is configured with redundant Gateways and one of the Gateways is quiesced, the redundant Gateway cannot be the replacement Gateway for the quiesced Gateway.
- For a customer deploying a NSD via Gateway where BGP is configured on the NSD, if the customer migrates the NSD to a different Gateway using the Self-Service Gateway Migration feature on the Orchestrator, the BGP configurations are not migrated and all BGP sessions are dropped post-migration.
In this scenario, the existing Gateway assigned to the NSD is in a quiesced state and requires migration to another Gateway. The customer then navigates to Service Settings > Gateway Migration on the Orchestrator and initiates the Gateway Migration process to move their NSD to another Gateway. Post-migration, the BGP Local ASN & Router ID information is not populated on the new Gateway and results in NSD BGP sessions not coming up with all routes being lost and traffic using those routes is disrupted until the user manually recreates all BGP settings.
This is a Day 1 issue and while the Gateway Migration feature accounts for many critical NSD settings, the NSD's BGP settings that are not accounted for, and their loss post-migration is an expected behavior.
Workaround: The migration of a Gateway should be done in a maintenance window only. Prior to the migration, the user should document all BGP settings and be prepared to manually reconfigure these settings post-migration to minimize impact to customer users.
